LncRNA MIAT/miR-384-5p在急性心肌梗死大鼠中的作用机制研究  

Study on the action mechanism of lncRNA MIAT/miR-384-5p in rats with acute myocardial infarction

作　　者：李灿 陈卉彬 简洁 LI Can;CHEN Huibin;JIAN Jie(Guangxi Key Laboratory of Diabetic Systems Medicine,Guilin 541199,China)

机构地区：[1]广西糖尿病系统医学重点实验室,桂林541199

出　　处：《广西医科大学学报》2025年第2期233-240,共8页Journal of Guangxi Medical University

基　　金：国家自然科学基金资助项目(No.81760726);广西硕士研究生创新项目资助(No.YCSW2024457)。

摘　　要：目的:探讨抑制lncRNA MIAT对大鼠急性心肌梗死(AMI)的作用及其分子机制。方法:将60只雄性SD大鼠随机分为假手术组、AMI组、AMI+si-NC组、AMI+si-MIAT组、AMI+si-MIAT+miR-NC antagomir组、AMI+si-MIAT+miR-384-5p antagomir组。采取心肌原位多点注射的方法转染相应质粒,沉默大鼠lncRNA MIAT和miR-384-5p表达,转染24 h后,结扎心脏左冠状动脉前降支建立AMI模型(缺血24 h)。造模结束,应用生物信号采集系统观测心率(HR)、左心室间隔起搏(LVSP)、左心室舒张末期压(LVEDP)、左心室内压最大上升和下降速率(±dP/dtmax)的变化,TTC染色测量心脏梗死面积,苏木精—伊红(HE)染色观察心肌病理学变化,酶联免疫吸附试验(ELISA)法检测血清心肌钙蛋白Ⅰ(cTn-Ⅰ)含量,透射电镜(TEM)观察自噬小体数量,实时荧光定量PCR(RT-qPCR)检测lncRNA MIAT、miR-384-5p表达,蛋白质免疫印迹(western blotting)法检测自噬相关蛋白Beclin1、Cathepsin D和LC3表达。结果:与假手术组相比,lncRNA MIAT在AMI大鼠中的表达上调(P<0.01)。与AMI+si-NC组相比,敲低lncRNA MIAT后miR-384-5p表达上调;大鼠HR、LVSP、+dp/dtmax升高,LVEDP和-dp/dtmax降低,TTC和HE染色显示AMI大鼠心肌梗死面积减小,心肌细胞形态改善,血清cTn-Ⅰ含量降低,自噬小体数量减少,Beclin1、Cathepsin D与LC3蛋白表达水平降低(均P<0.05)。与miR-384-5p拮抗剂合用后,lncRNA MIAT的上述作用被显著逆转(均P<0.05)。结论:抑制lncRNA MIAT能减轻AMI大鼠心肌损伤,其作用可能与上调miR-384-5p表达、抑制自噬有关。Objective:To investigate the role and molecular mechanism of lncRNA MIAT inhibition in acute myocardial infarction(AMI)in rats.Methods:Sixty male Sprague-Dawley(SD)rats were randomly divided into sham,AMI,AMI+si-NC,AMI+si-MIAT,AMI+si-MIAT+miR-NC antagomir,and AMI+si-MIAT+miR-384-5p antagomir groups.The target plasmids were transfected into the myocardial tissue through in situ multi-point injections to silence the expression of lncRNA MIAT and miR-384-5p in rats.After 24 hours of transfection,the AMI model was established by performing ligation of the left anterior descending branch of the coronary artery of the heart for a duration of 24 hours.After completing the modeling,the changes of heart rate(HR),left ventricular systolic pressure(LVSP),left ventricular end-diastolic pressure(LVEDP)and the maximum rate of rise and fall of left ventricular pressure(±dP/dtmax)were gauged by biosignal acquisition system.The 2,3,5,triphenyl-2Htetrazolium chloride(TTC)staining was used to determine the infarct size and the pathological changes in cardiomyocytes were observed by hematoxylin-eosin(HE)staining.The level of serum cardiac troponin-Ⅰ(cTn-Ⅰ)was detected by enzyme-linked immunosorbent assay(ELISA).Transmission electron microscope(TEM)was used to observe the number of autophagosomes.Reverse transcription-quantitative polymerase chain reaction(RTqPCR)was used to detect lncRNA MIAT and miR-384-5p gene expression,and western blotting was used to detect autophagy-associated proteins Beclin1,Cathepsin D and LC3 expression.Results:Compared with the sham group,the expression of lncRNA MIAT was increased in rats with AMI(P<0.01).Compared with the AMI+si-NC group,the knockdown of lncRNA MIAT led to an upregulation of miR-384-5p expression,an increase in the levels of HR,LVSP and+dp/dtmax,and a decrease in the levels of LVEDP and-dp/dtmax.TTC and HE staining revealed a decreased myocardial infarct size in AMI rats and improved cardiomyocyte morphology.Additionally,serum cTn-I levels were significantly reduced,the number of a

关 键 词：lncRNA MIAT 急性心肌梗死 miR-384-5p 自噬 

分 类 号：R542.22[医药卫生—心血管疾病]